A female member of the Ahbab Al-Mustafa Battalion holds a gun as she undergoes military training in Aleppo's Salaheddine district, June 24, 2013. (Photo by Muzaffar Salman/Reuters)

People stroll alongside one of the hills of the Tio Pio park in Madrid, Monday, January 25, 2016. The park is a high viewpoint frequented mostly by locals due to its view of the Spanish capital skyline. (Photo by Francisco Seco/AP Photo)

President Calvin Coolidge rides in a car during his inaugural parade in Washington, D.C., U.S. in March 1925. (Photo by Reuters/Library of Congress)

Thailand’s Sanctuary of Truth is an all-wood building filled with sculptures based on traditional Buddhist and Hindu motifs. It is covered in intricate wood carvings, meant to depict complex ideas about ancient thought, human responsibility, and the cycle of life. (Photo by Yury Taranik/Getty Inages)

A string is used to ensure that the skirts of female members of the honour guard are in the same height from the ground as they prepare for a welcoming ceremony for Congo Republic President Denis Sassou Nguesso outside the Great Hall of the People in Beijing, China, July 5, 2016. (Photo by Jason Lee/Reuters)

Undated handout photo of members of Ballet Ireland during a photocall on Edinburgh's Calton Hill before taking part in the Edinburgh Festival 2018 in Edinburgh, Scotland. Issue date: Tuesday, August 7, 2018. (Photo by Julie Howden/Culture Ireland/PA Wire)

Members of the Bearded Ladies Cabaret cross Broad St., before a march by supporters of Sen. Bernie Sanders, I-Vt., in Philadelphia, on the first day of the Democratic National Convention, July 25, 2016. (Photo by Tom Williams/CQ Roll Call/AP Images)

The northern lights, or aurora borealis, appear in the sky over the Bamburgh lighthouse at Stag Rock in Northumberland, England on September 28, 2016. (Photo by Owen Humphreys/PA Wire via ZUMA Press)